wait...i thought the sgl-31-94 came with a pg reinforcement plate?I just had Two River Arms do some work on my Sgl 31-94...they welded the barrel pins on the fsb and gas block over, did faux punch pressed divits on them, cyrillic selector marks and 74 selector hashes, installed a pg reinforcement plate and finished the gun in "techno" paint...it's now a nice looking 74m clone...TRA really does some nice work...
I have rifles built by TRA and Brendyn - they do great work and I've got kits at, or ready to send to, both builders right now - but a complete answer to your question should include Marshall Arms. Ted can't be beat by anyone in terms of dead-on, detailed accuracy of a 100-series clone (although he needs to adopt the new paint standards and customers should insist on this). Others would have mentioned MA but it's been difficult to get in the door due to demand for his work and a serious car accident that prevented or severely limited his AK-building work over the last couple years. He's working to overcome this and hopes to be able to take on more work in the future.
Both TRA and Ted Marshall told me the ATF does not allow this anymore.What about removing the horrible other markings? I have been over the ATF regs and it does seem to me that only the serial number cannot be touched. The stupid dot matrix import marks should be good to weld over and remove no?